Chassis for mounting component units of an electric switch cabinet for elevators and escalators

ABSTRACT

A chassis ( 11 ) for mounting component units ( 17, 19 ) of an electric switch cabinet for elevators and escalators, comprising at least one shaped part ( 15 ) serving as main supporting member, said shaped part being composed with a plastics material of lasting resetting force with respect to compression and being provided with at least one receiving recess ( 29, 31 ) for receiving a component unit ( 17 ) of a first type in substantially form-locking manner, and comprising at least one mounting rail ( 21 ) serving as auxiliary supporting member and anchored in the shaped part ( 15 ), said mounting rail ( 21 ), at least over a predetermined partial length thereof, being accessible in a free space ( 42 ) of the shaped part ( 15 ) for mounting at least one component unit ( 19 ) of a second type to said mounting rail ( 21 ), with said free space ( 42 ) being designed to selectively receive component units of the second type in different numbers, shapes and sizes.

TECHNICAL FIELD

The invention relates to a chassis for mounting component units in anelectric switch cabinet for elevators and escalators.

BACKGROUND ART

For control of electric elevators and escalators, there are requiredelectric control means that are usually accommodated in control orswitch cabinets installed in a machine room or hoistway in a building orin an escalator or moving steps. Such switch cabinets conventionallyhave a sheet metal housing having attached thereto component units, forexample, circuit boards, relays, capacitors, transformers etc., by meansof frame parts, screws, spacer bolts, brackets etc. One thus arrives ata large amount of parts. It is quite cost-intensive and time-consumingto manufacture all necessary parts, to mount and assemble them and todisassemble them again for maintenance, repair or recycling purposes.

DE 36 12 511 A discloses a distribution cabinet comprising a housing anda component carrier inserted in the housing. The housing comprises arigid frame consisting of square metal sections and having verticalsupports and horizontal rails as well as struts extending along thehousing edges. A bottom part, a cover part and side parts of the housingare formed by shaped parts of rigid expanded plastics material and areprovided with mounting blocks for mounting the apparatus carrier andwith reinforcing ribs. The component carrier has rails for attachment ofelectrical instruments and equipment. Such a distribution cabinetconsists of a plurality of individual components that have to beconnected to each other by connecting members and is relatively heavy.

For heavyweight components, such as e.g. transformers or filters, thereis a particularly high risk of damage, for instance in the form ofbroken bolts, screws, anchorages, etc., as a result of vibrations orshocks during transport. Switch cabinets for elevators and escalatorsfurthermore contain noise generating components, such as power switchesand relays. Thus, sound-absorbing materials must additionally beaccommodated in such a switch cabinet.

It is known from U.S. Pat. No. 5,644,472 A to reduce the assembly costfor desktop computers by inserting individual components of such acomputer, such as the main board along with the processor, the fixeddisk and the fan, into recesses matched to the shape thereof which areformed in a carrier of foamed urethane material composed of an uppercarrier part and a lower carrier part, to thereby maintain thecomponents in their desired positions. Although these components arefirst held in positive or form-locking manner by the foamed urethanematerial, it may happen due to vibrations or shocks during transport orduring operation of such a desktop computer that the receiving recessesfor the individual components are undesirably increased since the foamedurethane material does not have a sufficient resetting force withrespect to compression forces, so that deformations of the receivingrecesses as a result of vibration and/or shock forces are permanent.This may be counteracted according to the reference, by attaching someor all of the components accommodated in the carrier to the carrier bymeans of fastening elements such as screws, brackets etc. However, thisin turn causes a corresponding increase in manufacturing and mountingcost.

It is known from DE 91 16 755 U1 and the corresponding U.S. Pat. No.5,473,507 A to make such a carrier for a computer or a measuringapparatus of expanded polypropylene (EPP), a material with highstability in shape and elastic resetting force with respect tocompression. Individual components of the computer, such as inparticular a fan, a fixed disc, a main board, a loudspeaker andcapacitors, are each inserted in a receiving cavity of the carrier thatis closely matched to the outer shape of the particular component. Dueto the high resetting force of the plastics material used and the snugfit of the individual components, the components are permanentlyretained in their position. There are thus no additional fasteningelements provided, so that an overall reduction in manufacturing andmounting cost is obtained.

However, such carriers are designed for receipt of comparativelylight-weight computer components which remain identical in their outershape for various computer models, and are not suited without furtherado as carriers for elevator and escalator switch cabinets that mustcarry components or components units that are not only relatively heavyin part, but which in part may also have quite different shapes and/ormay be provided in different numbers, depending on the particular modeland intended application of the particular switch cabinet. If theconception of the above-mentioned carriers were used for computers forelevator and escalator switch cabinets, a matched shaped plastics partof its own would have to be produced for each switch cabinet model,which would require a corresponding number of injection molds. In thelight of the comparatively low number of pieces per switch cabinet modelfor escalators and elevators, as compared with mass-produced apparatuslike computers, this would constitute an unbearable cost expenditure.

DISCLOSURE OF INVENTION

It is the object of the invention to make available a chassis of thetype indicated at the outset, through which the manufacturing andmounting costs for elevator and escalator switch cabinets can be reducedby making use of the afore-mentioned conception for carriers of computercomponents, while simultaneously reducing the possibility of damages,and improving both noise attenuation as well as usability for variousswitch cabinet models.

A chassis of the type according to the invention comprises a shaped part(molded part) serving as main supporting member, which is composed witha plastics material with lasting resetting force with respect tocompression and is provided with at least one receiving recess forreceiving a component unit of a first type in substantially positivesnug fitting or form-locking manner. In addition thereto, a chassis ofthe type according to the invention is provided with at least onemounting rail serving as auxiliary supporting member and anchored in theshaped part, said mounting rail, at least over a predetermined partiallength thereof, being accessible in a free space of the shaped part formounting at least one component unit of a second type to said mountingrail, with said free space being designed and dimensioned such that suchcomponent units of the second type can be received in different numbers,shapes and sizes.

In an embodiment of the invention, the shaped part consists of expandedpolypropylene (EPP). However, any other plastics material with stabilityin shape and sufficient lasting resetting force as regards compressionmay be used as well. Alternative materials are, for instance,polyurethane and polyethylene. Plastics materials are preferred that canbe injection-molded in an injection mold also as larger shaped parts.

Each of the component units of a first type has associated therewith areceiving recess of its own of the chassis, which is closely matched tothe outer shape of the respective component unit and receives thiscomponent unit to a predetermined insertion depth. Preferably, therespective receiving recess is dimensioned such that the associatedcomponent unit is received therein in a press fit. Due to the highresetting force of the plastics material used, a holding force isexerted on the respective component unit such that it is permanentlyheld in its position. The component units of the first type merely needto be inserted in the receiving recesses provided therefor, so that anoverall reduction of the manufacturing and mounting expenditure isobtained. For such component units, in the event they are too heavy tobe still safely held in their receiving recesses by the resetting forceof the plastics material of the shaped part also in case of tipping ofthe chassis, there may be provided additional fastening elements forsafely fixing such component units.

Due to the fact that supporting rails, supporting frames and othersupporting members of conventional switch cabinets for elevators,escalators and moving steps have all been replaced by a shaped part ofplastics material, there chassis according to the present inventionachieves considerable noise attenuation as compared to the prior art.This is enhanced still further if noise-generating component units, inthe receiving recesses thereof, are surrounded in part by thenoise-absorbing plastics material of the shaped part.

In a plastic shaped part as used for the chassis according to theinvention, cooling air can be directed and channelled more effectivelythan in conventional switch cabinets. The cooling air can be betterdirected towards component units requiring cooling, so that a reducedcooling capacity is sufficient or an increased cooling efficiency can beobtained.

In a preferred embodiment of the invention, the chassis is open at leastin the upward direction. The individual component units thus are notenclosed on all sides, but project upwardly from the respectivelyassociated receiving recesses providing especially good accessibility inthe event of maintenance or repair as well as facilitated cooling arerendered possible.

Due to the fact that the component units of the second type are notreceived in a receiving recess designed to receive the same in a snug orform locking manner, but are received in the free space of the shapedpart that is not configured on the shape thereof, increased flexibilityto the effect is obtained that mutually different circuit arrangementscan be arranged in a specific chassis, for example circuit arrangementswith different power demands having power components in differentnumbers and/or of different shape. Those component units that areidentical for all different circuit arrangements (components units ofthe first type) are received in a form-locking manner by receivingrecesses that are matched to the outer configuration thereof Thosecomponent units which for the different circuit arrangements are ofdifferent shape or size or are present in different numbers (componentunits of the second type), are accommodated in one or more free spacesof the shaped part. The result of this embodiment according to thepresent invention is that it is not necessary to manufacture a shapedpart of its own for receiving each circuit arrangement of differenttype, but that identical shaped parts may be used for a larger number ofdifferent circuit arrangements. This leads to a considerable reductionin manufacturing costs as a larger number of shaped parts can beproduced using one injection mold.

Due to the fact that the component units of the second type are not heldwith the aid of the resetting force of the plastics material of theshaped part, the chassis according to the present invention provides atleast one mounting rail that is anchored in the shaped part and isaccessible in the region of the free space for mounting one or morecomponent units of the second type.

The component units of the second type thus in the end are carried bythe shaped part of the chassis as well, however not directly, like thecomponent units of the first type, but by means of the mounting rail.

A further advantage in using a mounting rail consists in that the loadof a component unit mounted to the mounting rail, by means of thesupporting rail, can be introduced into areas of the shaped part which,due to the overall shape of the shaped part, are capable of supportingparticularly high loads, possibly to a much higher extent than thoseareas of the shaped part adjacent the component unit mounted to thesupporting rail.

Preferred as mounting rails are rails that have become widely availableand standard in switch cabinet construction. Particularly preferred areso-called top hat rails according to European standards EN 50022 and EN50045 as well as so-called C-rails according to EN 50035. However, otherconstructions may be used as well, such as, for example, perforatedrails and perforated angle pieces, threaded hole rails and threaded holeangle pieces as well as profiled rails of other types that serve forinstallation of components.

A top hat rail is an approximately U-shaped rail having a rail bottomwith a rail side wall upstanding from each of the two longitudinal sidesthereof, the free end of each side wall being provided with a rail edgeprojecting outwardly from the respective rail side wall and serving forattachment of component units with fasting elements of complementarydesign. In preferred embodiments of the invention, the mounting railconsists of metal. However, it may also be made of ceramics or plasticsmaterial of sufficient hardness, dimensional stability and breakingstrength.

In a further embodiment of the invention, the mounting rail is held inthe shaped part so as to be longitudinally slidable to provide foreasier insertability of the mounting rail in the shaped part and easierassembly of one or more component units of the second type in the freespace at the mounting rail. The longitudinal slidability of the mountingrail in both of its longitudinal sliding directions may be unlimited, inparticular if the chassis, in the state of use thereof, is received inan enclosing casing or switch cabinet housing that limits thelongitudinal sliding motion of the mounting rail in both directions. Alimitation of the longitudinal slidability of the mounting rail, atleast in one of its longitudinal sliding directions, may also beobtained by a longitudinal sliding motion stopper formed in the shapedpart.

In a still further embodiment of the invention, a rail anchoring elementis releasably mounted in at least one longitudinal location of themounting rail, with said rail anchoring element being received in ananchoring receiving opening of the shaped part of approximately matchingshape. The rail anchoring element, for example, is an about disk-shapedplastic part that is slid onto the mounting rail and surrounds inparticularly the outer edges thereof so that these cannot cut into theplastics material of the shaped part. Moreover, the rail anchoringelement can be provided with a disk area that is much larger than thecross-sectional area of the mounting rail, whereby the pressing forceexerted by the mounting rail can be distributed via the rail anchoringelement to a considerably larger area of the shaped part than in case ofthe direct receipt of the mounting rail by the shaped part.

In case the chassis is to accommodate component units which, for examplewith regard to their weight, should be secured in particular manneragainst the effects of vibrations, shocks and tipping of the chassis,such as during transport thereof, an embodiment of the inventionprovides for the arrangement of at least one dowel-like fasteningelement in a surface of the shaped part, at which such a component unitcan be fixed, either directly or by means of a holding device betweenthe component unit and the dowel-like fastening element. As such adowel-like fastening element, there is suitable in particular a dowelwith large radial anchoring area that was developed for sandwich typeplaster boards and is available e.g. from the company Fischer (ArthurFischer GmbH & Co. KG, Weinhalde 14-18, D-72178 Waldauchtal, Germany)under the designation GK. By means of this anchoring area, tensileforces exerted on the dowel in case of acceleration forces of the typementioned, are converted primarily to compression forces with respect tothe plastics material of the shaped part. Thus, the plastics material ofthe shaped part is subject predominantly to compression forces which theshaped part plastics material of the type preferred can withstand to amuch higher extent than tensile forces.

In a chassis according to the invention, electric connecting cables mustbe accommodated for electrically interconnecting component units and/orapparatus located inside the chassis and/or outside the chassis. In apreferred embodiment of the invention such cables are housed in one ormore cable ducts that are molded in the shaped part. In the event thatthe chassis accommodates component units in different numbers and/or ofdifferent power categories, electric connecting cables in correspondingnumbers and/or of corresponding diameter must be accommodated as well.At least one cable duct of the chassis thus is preferably designed suchthat it is capable of accommodating different numbers of cables and/orcables of different thicknesses. In a particularly preferred embodiment,at least one cable duct is provided with at least one strain reliefmeans. The strain relief may be formed by strain-relieving constrictionsof the respective cable duct, into which at least one cable is urged.Along the cable duct, there may also be provided severalstrain-relieving constrictions so as to ensure that cables of shortlength are supported by at least one strain-relieving location, and thatcables of greater length experience strain-relief at several locationsalong their longitudinal extension.

Particularly high strain relief for a cable to be inserted in thechassis is obtained in a still further embodiment of the invention inwhich the cable is placed in the injection mold for molding the shapedpart and, during injection molding of the shaped part, is embedded inthe shaped part plastics material in strain-relieving manner.

In a still further embodiment of the invention the shaped part has atleast one fan receiving recess for receipt of at least one motor-drivenfan for ventilating a ventilation space of the shaped part. Theventilation space is constituted in essence by the entire empty space ofthe shaped part that is not filled with shaped part plastics materialand component units inserted in the shaped part.

Unlike in traditional switch cabinets in which cooling air circulates insubstantially uncontrolled manner through the entire switch cabinetinterior, a chassis according to the invention, due to the configurationof the shaped part, can ensure purposeful cooling air control andcooling air distribution. By corresponding design of the empty space ofthe shaped part, the cooling air may be directed in more purposefulmanner to component units with a higher need of cooling.

Due to the fact that as in a conventional switch cabinet in which theentire interior of the switch cabinet constitutes the ventilation space,the chassis according to the present invention uses only the empty spaceof the shaped part, which can be designed purposefully, so that acomparatively low power fan is sufficient to generate a positiveventilation pressure which prevents the ingress of dust or other dirtparticles into the interior of the switch cabinet, with the air suckedin by the fan being filtered. The effect achieved thereby is that onlyfiltered air reaches the interior of the switch cabinet and unfilteredair cannot enter into the switch cabinet interior via slots, cranniesand other openings which cannot be avoided in switch cabinet housings ofthe usual kind. The danger of contamination of the switch cabinetinterior due to unfiltered air is particularly high for elevator switchcabinets and escalator switch cabinets since such switch cabinets arearranged in machine rooms or hoistways and escalators, which usually arenot, or only with difficulty, accessible for regular overall cleaning,so that much dust and dirt accumulates in such spaces in the course oftime.

In practical application, a chassis according to the invention issurrounded by an enclosing housing or enclosure. The latter may beformed in particular by a switch cabinet housing accommodating at leastone chassis according to the invention. This enclosure may also bedesigned such that it limits the longitudinal slidability of a mountingrail inserted in the shaped part of the respective chassis in at leastone longitudinal sliding direction.

In an embodiment of the invention in which a plurality of chassis of thetype according to the invention are accommodated in a switch cabinet,each chassis would constitute a module adapted to be separately insertedinto and removed from the switch cabinet. Preferably, each module has atleast one fan of its own, with the overall ventilation system beingdesigned such that an excess ventilation pressure is created in theswitch cabinet.

In a particularly preferred embodiment of a switch cabinet according tothe invention, the switch cabinet housing and at least one chassis aredimensioned such that the chassis is accommodated in the switch cabinethousing in a press fit. This has the effect that the side walls of theswitch cabinet have to bear only the weight of the one chassis loadedand the switch cabinet cover, but need not have lateral stability oftheir own, since the latter is given to them by the one chassisaccommodated in a press fit.

By way of comparison, a typical prior art elevator switch cabinetcomprises a switch cabinet housing having a rear wall with a thicknessof 3 mm, to which a transformer and other heavy parts must be bolted orotherwise firmly secured. The remaining walls of this switch cabinethousing have a sheet metal thickness of 1 to 1.5 mm. This switch cabinethousing has a weight of approximately 50 kg.

In a comparative embodiment of an elevator switch cabinet used with achassis according to the present invention, a sheet-metal thickness of0.8 mm is sufficient for all walls of the switch cabinet housing,thereby reducing the overall weight of the switch cabinet housing to 15kg.

The invention can be utilized also with frequency converters for whichpower semiconductor components of high voltage compatibility and/orperformance are employed. A frequency converter according to theinvention comprises a frequency converter housing accommodating at leastone chassis having the features of a chassis according to the inventionas claimed and described hereinbefore.

The invention as well as further objective aspects and advantages of theinvention will now be elucidated in more detail by way of embodiments.These relate to a switch cabinet for elevators or escalators whichcontains three modules, namely a control module, a frequency convertermodule (hereinafter referred to as drive module) and a filter module,with one chassis according to the invention each.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a perspective view of an inventive chassis of a controlmodule, that is partly equipped with component units;

FIG. 2 shows a perspective, exploded view of the chassis of FIG. 1,illustrating component units and components prior to insertion thereofin the chassis;

FIG. 3 shows a plan view of the chassis according to FIGS. 1 and 2 priorto providing the same with component units and components;

FIG. 4 shows a plan view similar to FIG. 3, however after insertion ofcomponent units and components;

FIG. 5 shows a perspective view of a chassis according to the inventionfor a drive module prior to the provision of component units andcomponents, along with an exploded view as regards a ventilation grid;

FIG. 6 shows a plan view of the chassis shown in FIG. 5 with assembledventilation grid;

FIG. 7 shows a bottom side view of the chassis shown in FIG. 6;

FIG. 8 shows a perspective view of a circuit arrangement comprising thecontrol module shown in FIGS. 1 to 4, the drive module shown in FIGS. 5to 7 and an additional filter module, which are accommodated in a commonenclosure, as seen in a plan view of a first longitudinal side;

FIG. 9 shows the circuit arrangement of FIG. 8 in an exploded view,before accommodation thereof in the common enclosure;

FIG. 10 shows a perspective view of the circuit arrangement of FIG. 8,as seen in a plan view of a second longitudinal side; and

FIG. 11 shows an exploded view of the circuit arrangement of FIG. 10prior to accommodation thereof in the common enclosure.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows in a perspective view an embodiment of a chassis 11according to the invention for a control module 13 of the circuitarrangement shown in FIG. 8. Chassis 11 has a shaped part 15 which iscomposed of a plastic material with lasting resetting force with respectto compression. In FIG. 1, shaped part 15 is shown equipped only with afew of the component units and components of the finished control module13, namely with a fan 17, a relay 19, a mounting rail 21, at least tworail anchoring elements 23, of which only one can be seen in FIG. 1, anddowels 25, of which only two can be seen in FIG. 1, for fixation of atransformer (not shown).

Shaped part 15 is provided with an approximately circular transformerreceiving recess 29 and with an approximately U-shaped fan receivingrecess 31. Both receiving recesses 29 and 31 are designed anddimensioned such that they receive the fan 17 and the transformer,respectively, in substantially form-locking manner over a substantialpart of their respective circumference, so as to be in a press fit, sothat they are thereby retained in their position with the aid of theresetting force of the plastic material of the shaped part.

In addition to the two aforementioned receiving recesses 29 and 31,shaped part 15 has further receiving recesses, all designated 33 butserving to accommodate different component units, for example fuses,electronic control means etc. Moreover, shaped part 15 is provided withtwo upwardly open cable ducts 35 each having a meander-like channelshape and being each provided with a plurality of strain-relievingconstrictions 37.

The transformer receiving recess 29 is approximately of circular shapeand is provided on the one hand at several circumferentially distributedlocations with compression ribs 39 and with recesses or teeth 41 on aside about diagonally opposite said compression ribs 39; said recessesor teeth 41 adapted to permit the transformer connecting cables (notshown) to be passed therethrough. As shown in FIG. 3, the region inwhich teeth 41 are located is recessed with respect to the peripheraledge of transformer receiving recess 29 at which dowels 25 are provided.When the transformer is mounted, this recess is covered by a roof-likesealing lip 27. The sealing lip thus provides both a substantiallyairtight seal for preventing a flow of cooling air past the sealing lip,and a cable feed-through avoiding pinching of the transformer cables.The sealing lip is elastically yielding in the region of the cable andthus seals around the cable and the teeth 41. In addition thereto,shaped part 15 has a free space 42 accommodating component units of thesecond type, which for the reasons indicated hereinbefore should not beaccommodated in a form-locking receiving recess, but in a space that isindependent of their shape.

Especially suited for a chassis 11 according to the invention is ashaped part 15 of expanded polypropylene (EPP) that is one of the knownresetting plastics and on the one hand displays particularly gooddimensional stability and on the other hand a particularly lastingresetting effect with respect to compression. For manufacturing theshaped part 15, polypropylene granulate is blown under pressure in acorrespondingly shaped injection mold. In addition thereto, hot steam isintroduced into the injection mold, which effects on the one handpopping open of the granulate into foamed beads of EEP and on the otherhand adhesion of the foamed beads so as to form the shaped part 15. Itis possible to influence the density and thus the resetting force of thefoamed plastics material of the shaped part 15 obtained in this mannerby controlling the quantity of granulate and the steam pressure.

The mounting rail 21 used for chassis 11 is preferably a so-called tophat rail according to European standards EN 50022 and EN 50045, which isavailable from the company WAGO (WAGO Kontakt-Technik GmbH, Hansastr.27, D-32385 Minden, Germany). The rail anchoring elements 23 cooperatingwith a mounting rail 21 of this type are available from WAGO as well.

The perspective exploded view of FIG. 2 shows component units andcomponents, which are already provided in shaped part 15 in the assemblyphase shown in FIG. 1, prior to insertion thereof in shaped part 15.FIG. 2 in particular shows, more clearly than FIG. 1, the shape of thefan receiving recess 31, the mounting rail 21 and of the rail anchoringelements 32. As regards the fan receiving recess 31, a retaining nose 43molded to shaped part 15 should be mentioned, below which the fanhousing is latchingly engaged after fan 17 has been urged into fanreceiving recess 31 in the direction indicated in FIG. 2.

Mounting rail 21 designed as top hat rail is an approximately U-shapedrail having a rail bottom 45 from both longitudinal sides of which thereis upstanding one rail side wall 47 each, with the free end thereofbeing provided with a rail edge 49 projecting outwardly from therespective rail side wall 47 and extending approximately parallel torail bottom 45. Components (not shown) that can be mounted to such amounting rail 21 have a matching, complementary shaped portion matchedto mounting rail 21 and additionally have holding parts engaging overthe rail edges 49, said holding parts permitting these components to beslid onto the mounting rail 21 from one end thereof or to be snappedonto the mounting rail 21 in a direction perpendicular to the railbottom 45. Rail anchoring elements 23 may be provided with a clampingmechanism (not shown in the drawings) which cooperates with a screwthreadedly engaged with the respective rail anchoring element 23 and, bymeans of this screw, is adjustable between a condition in which railanchoring element 23 can be slidingly moved on mounting rail 21 veryeasily, and a condition in which the rail anchoring element 23 is firmlyanchored in position to mounting rail 21.

For each of the two rail anchoring elements 23, there is provided inshaped part 15 an anchor receiving opening 51 of approximately matchingshape, with FIG. 2 showing only one thereof. In the embodiment shown,the anchor receiving opening 51, shown in FIG. 2, is configured toextend completely through the corresponding portion of shaped part 15,so that the mounting rail 21 can be slidingly inserted into the freespace 42 from the corresponding side. Thus, if relay 19 is adapted to besnapped onto the mounting rail from above, the left-hand rail anchoringelement 23 in FIG. 2, can be attached and fixed at the left-hand end ofmounting rail 21 and the assembled anchoring element and rail insertedinto free space 42 from the right-hand side in FIG. 2 through anchorreceiving opening 51 visible in FIG. 2.

If the mounting rail 21 does not extend over the entire width of shapedpart 15, so that the longitudinal slidability thereof, after insertionof shaped part 15 in an enclosing housing or enclosure, cannot beconfined by the same, one of the anchor receiving openings 51 can beprovided with a longitudinal sliding motion stopper which cooperates,for example, with the adjacent rail anchoring element 23, with anadditional stopper element being arranged on the outside of the otheranchor receiving opening 51 upon full introduction of mounting rail 21,with the mounting rail 21 being then hindered from a longitudinalsliding motion in both longitudinal sliding motion directions. If alongitudinal end of mounting rail 21, in the final position thereof,extends up to a side wall of shaped part 15, this additionallongitudinal sliding motion stopper may be part of the enclosure intowhich shaped part 15 is inserted.

FIG. 3 shows a top plan view of shaped part 15 of chassis 11 shown inFIGS. 1 and 2, prior to insertion of component units and components.FIG. 4 shows the same view of this shaped part 15, however afterinsertion of component units, namely the fan 17, the transformer and therelay 19, and of components, namely the mounting rail 21 and the railanchoring elements 23 (not visible in FIG. 4). The cable ducts 35 andthe strain-relieving constrictions 37 thereof are visible particularlyclearly in FIGS. 3 and 4.

The transformer receiving recess 29 is designed for receipt of anapproximately circular transformer, i.e. a ring core transformer. Thecircular shape of the transformer receiving recess 29 continues belowthe shaped part wall portion having the receiving recesses 33 formedtherein, in a manner not visible in FIGS. 3 and 4.

After insertion of the transformer (not shown) in the transformerreceiving recess 29, a cover part (not shown), for example of metal, isdisposed thereabove which is fastened to shaped part 15 by means ofdowels 25. The transformer then is secured against falling out from thetransformer receiving recess 29, for example in case of tipping over ofchassis 11.

FIGS. 5 to 7 show a second module of the circuit arrangement illustratedin FIG. 11, namely a drive module 53 containing a drive circuit of thecircuit arrangement.

In FIGS. 5 to 7 components and parts corresponding to components andparts of the control module illustrated in FIGS. 1 to 4, are designedwith the same numerals although they may differ in shape from thecorresponding components and parts of the control module.

The shaped part 15 of drive module 53 comprises capacitor receivingrecesses 55, resistor receiving recesses 57, a free space 59 for arelay, an energy supply unit receiving recess 61, i.e. a recess 69 forreceiving a heat sink with attached power components, cable ducts 35with cable-retaining and stress-relieving constrictions 37 as well asthree fan receiving recesses 31 best visible in FIGS. 6 and 7.

From fan receiving recesses 31, a first cooling air flow channel 65 anda second cooling air flow channel 67 extend to the region of thecapacitor receiving recesses 55. An outlet portion of first cooling airflow channel 65 is covered with a ventilation grid 69 serving as an airfilter, whereas an end portion of the second cooling air flow channel 67located in the region between the four capacitor receiving recesses 55is covered with a ventilation grid 71 also serving, in this embodimentas an air filter. In this manner, cooling air is introduced into theregion of the capacitor receiving recesses 55 purposefully and in acleaned state. The energy supply unit (not shown) is directly cooled byfan 31. This provides for positive cooling of the energy supply unit(not shown) and the capacitors (not shown either).

The capacitor receiving recesses 55 are downwardly open. That is to say,they have no downwardly closing floor. Underneath each capacitorreceiving recess 55 there is a supporting web 73 extending only overpart of the diameter of the respective capacitor receiving recess 55.This provides for considerably better cooling of the capacitors receivedby the capacitor receiving recesses 55 than if the capacitor receivingrecesses 55 had a closed cup shape. Supporting webs 73 support thecapacitors so that the latter can be introduced into the respectivecapacitor receiving recess 55 over a predetermined distance only. Fordifferently long capacitors with equal diameter, there may be providedsupporting webs 73 at different heights in the capacitor receivingrecesses 55. If a longer capacitor is to be inserted in such a receivingrecess 55, interfering supporting webs 73 provided for shortercapacitors simply can be broken off. In the extreme case, the capacitorprojects through the entire receiving recess 55 and all supporting webs73 are broken off. Preferably, the supporting webs 73 are provided suchthat inserted capacitors of different length terminate substantially atthe same height with respect to the edge of the receiving recess 55.

At least one side wall of at least one of the cable ducts 35 is formedwith narrow incisions 74 via which individual ones of the cables orwires inserted in the cable ducts 35 can be passed out of this cableduct 35 in lateral direction, with the incisions 74 being dimensionedsuch that they serve as strain relief for the cables or lines passedthrough the same.

FIGS. 8 to 10 show a circuit arrangement comprising control module 13,drive module 53 and a filter module 75 with a common switch cabinethousing 77; FIGS. 8 and 10 show the arrangement in an assembledcondition as seen in plan view from different longitudinal sides; FIGS.9 and 11 show the arrangement in exploded form as seen in plan view fromdifferent longitudinal sides.

Filter module 75 has a chassis and a shaped part constructed in similarmanner as in modules 13 and 53 described hereinbefore, though having adifferent shape. A detailed description of filter module 75 as well isthus not necessary. The general configuration thereof can be seen fromFIGS. 8 to 11.

Switch cabinet housing 77 forms an enclosure for the three modules 13,53 and 75. As can be seen best in FIG. 9, switch cabinet housing 77comprises a housing trough 79 having a housing bottom 81, and, withrespect to FIG. 9, a front longitudinal side wall 83, a rearlongitudinal side wall 85, a left-hand narrow side wall 87 and aright-hand narrow side wall 89. In the assembled state of the switchcabinet, housing trough 79 is closed by means of a housing cover 91.

At the left-hand narrow side wall 87, there are mounted jack rings 93 inthe assembled state of switch cabinet housing 77, by means of which thefinished switch cabinet 95 can be lifted and transported to apredetermined location of a hoistway wall or the escalator. The switchcabinet 95 is mounted there in such a manner that the jack rings 93 aredisposed at the top and the right-hand narrow side wall 89 in FIG. 9 isdisposed at the bottom, with the housing bottom 81 abutting the wall ofthe hoistway or escalator, respectively.

On the inside of housing bottom 81 there is provided a supporting rail97. On the top side thereof directed upwardly in FIG. 9, there ismounted an electric connector 99. When switch cabinet 95 is attached tothe hoistway wall, supporting rail 97 serves to support the weight ofthe transformer accommodated in control module 13 as pressure force onthe shaped part 15 of control module 13. To this end, supporting rail97, in the finished condition of switch cabinet 95, projects into acomplementary supporting recess in the bottom side of shaped part 15 ofcontrol module 13. In the embodiment shown in the figures, thissupporting recess 101 constitutes a passage through the entire width ofthe shaped part 15 of control module 13, so that electric connector 99is visible in plan view in FIGS. 8 and 9.

The longitudinal side walls 83 and 85 have air inlet or air dischargeopenings 103. On the outside of each longitudinal side wall 83, thereare provided, from the inside towards the outside, a grid-like spacermember 105, a filter mat 107 and a filter mat cover plate 109 that isalso provided with air discharge openings 103. In FIG. 11, spacer member105, filter mat 107 and filter mat cover plate 109 are shown in the formof a mounting unit 111 that can be fastened to the respectivelongitudinal side wall 83 by means of suitable fastening members. Shownon the left-hand end of housing bottom 81 in FIG. 9 are mounting holes113 cooperating with wall mounting members on the hoistway wall on whichswitch cabinet 95 is to be suspended.

FIGS. 9 and 11 show, at the end of switch cabinet housing 77 oppositethe jack rings 93, top hat rail pieces 115 which are riveted to housingbottom 91 and are provided with clamping rails 117 carrying groundingterminals.

FIGS. 9 and 11 show reinforcing angle pieces 119 by means of whichstiffening of switch cabinet housing 77 is obtained.

Housing cover 91 is provided with locking members 121 by means of whichit can be locked to housing trough 79. The housing cover is providedfurthermore with air discharge openings (not shown) for exhaust air thatwas inducted through opening 103 in side wall 85 and then was used foractive cooling of the switch cabinet components as described above.

In so far as details of the above-elucidated chassis, modules andhousings have not been described, reference is made to the detailedrepresentations in the drawings.

A chassis according to the invention can also be used well for frequencyconverters having semiconductor components designed for high powerand/or high voltages. Such a chassis for a frequency converter, justlike the modules described hereinbefore, comprises a shaped part formedwith receiving recesses and free spaces and, if necessary, having atleast one mounting rail and/or dowel. This chassis, too, can beaccommodated in an enclosure or in an apparatus housing. Differencesfrom the afore-described modules for an elevator or escalator switchcabinet are present merely with respect to the specific configuration ofthe shaped part and the electric and mechanical component units to beaccommodated therein. A detailed description of such a frequencyconverter is thus not necessary.

What is claimed is:
 1. A chassis (11) for mounting component units (17,19) of an electric switch cabinet for elevators and escalators,comprising: at least one shaped part (15) serving as main supportingmember, which consists of a plastic material with lasting resettingforce with respect to compression and is provided with at least onereceiving recess (29, 31) for receiving a component unit (17) of a firsttype in a substantially form locking manner, and comprising at least onemounting rail (21) serving as auxiliary supporting member and anchoredin the shaped part (15), said mounting rail (21), at least over apredetermined partial length thereof, being accessible in a free space(42) of the shaped part (15) for mounting at least one component unit(19) of a second type to said mounting rail (21), with said free space(42) being designed to selectively receive component units of the secondtype in different numbers, shapes and sizes.
 2. The chassis of claim 1,wherein the shaped part (15) is at least upwardly open.
 3. The chassisof claim 1, wherein the mounting rail (21) thereof is constituted by anapproximately U-shaped rail having a rail bottom (45) with a rail sidewall (47) upstanding from both longitudinal sides thereof, the free endof each rail side wall being provided with a rail edge (49) projectingoutwardly from the respective rail side wall (47) and serving forattachment of component units (19) of a second type by means offastening elements of complementary design.
 4. The chassis of claim 3,wherein the mounting rail (21) thereof is composed with metal.
 5. Thechassis of claim 4, wherein the mounting rail (21) thereof is held inthe shaped part (15) so as to be longitudinally slidable therein.
 6. Thechassis of claim 5, wherein the longitudinal slidability of the mountingrail (21) within the shaped part (15) is unlimited in at least onelongitudinal sliding direction.
 7. The chassis of claim 6, wherein thelongitudinal slidability of the mounting rail (21) within the shapedpart (15) is unlimited in one longitudinal sliding direction and islimited in the opposite direction by a side wall (85) of a switchcabinet housing (77).
 8. The chassis of claim 1, wherein in at least twospaced apart locations along the length of the mounting rail (21), thereis releasably mounted one rail anchoring element (23) each which isreceived in an anchor receiving opening (51) of shaped part (15) ofapproximately matching shape.
 9. The chassis of claim 8, wherein a firstone of said two anchor receiving openings (51) is configured to extendcompletely through the insert (15) and permits free longitudinalslidability of the respective associated rail anchoring element (23).10. The chassis of claim 1, wherein at least one dowel-like fasteningelement (25) is introduced in a surface of the shaped part (15).
 11. Thechassis of claim 1, wherein a least one cable receiving duct (35) isintroduced into the shaped part (15), said cable duct (35) beingprovided with at least one strain relief means (37).
 12. The chassis ofclaim 11, wherein the cable duct (35) thereof is provided with at leastone cable strain relieving constriction (37).
 13. The chassis of claim1, wherein at least one fan receiving recess (31) is provided forreceipt of at least one motor-driven fan (17) for ventilation of aventilation space of the shaped part (15), with cooling air flowchannels (65, 67) being formed in said ventilation space.
 14. Thechassis of claim 13, comprising at least one cooling air filter (107).15. The chassis of claim 14, wherein at least one of said cooling airfilters is disposed adjacent a grid-like spacer (105).
 16. The chassisof claim 1, wherein the shaped part (15) is enclosed by an enclosure(77).
 17. The chassis of claim 16, wherein the longitudinal slidabilityof the mounting rail (21) is limited in at least one of said twolongitudinal sliding directions by said enclosure (77).
 18. An electricswitch cabinet for elevators and escalators, comprising a switch cabinethousing (77) having at least one chassis (11) including at least oneshaped part (15) serving as main supporting member, which consists of aplastic material with lasting resetting force with respect tocompression and is provided with at least one receiving recess (29, 31)for receiving a component unit (17) of a first type in a substantiallyform locking manner, and comprising at least one mounting rail (21)serving as auxiliary supporting member and anchored in the shaped part(15), said mounting rail (21), at least over a predetermined partiallength thereof, being accessible in a free space (42) of the shaped part(15) for mounting at least one component unit (19) of a second type tosaid mounting rail (21), with said free space (42) being designed toselectively receive component units of the second type in differentnumbers, shapes and sizes.
 19. The switch cabinet of claim 18, havingseveral chassis (11) accommodated therein which are each part of amodule (13, 53, 75) adapted to be separately inserted into said switchcabinet (95) and removed from said switch cabinet (95).
 20. The switchcabinet of claim 18, including a ventilation system containing at leastone fan (17) and at least one cooling air flow channel (65, 67), saidchannel configured such that an excess ventilation pressure can begenerated in the switch cabinet.
 21. The switch cabinet of claim 18,wherein the longitudinal slidability of the mounting rail (21) islimited in at least one of the two longitudinal sliding directions by aside wall (83, 85) of the switch cabinet (95).
 22. The switch cabinet ofclaim 18, wherein the switch cabinet housing (77) and the at least onechassis (11) are dimensioned such that the chassis (11) is accommodatedin a press fit in the switch cabinet housing (77).